The invention relates to harvesters, but more particularly, the invention relates to a conveying belt with at least one working element attached exteriorly thereto.
In harvesting equipment, it is sometimes advantageous to use belts for performing work in addition to or other than their normal function of power transmission. One or more working elements may be attached at the belt exterior as shown in U.S. Pat. Nos. 3,545,188 and 3,831,358. These patents disclose various means for attaching different cutters or working elements to belts. While such attachments are satisfactory for high speed cutting where the cutters are stabilized by guide bars, or centrifugal or gyroscopic forces, such attachments have not proven satisfactory for low speed cutting belts with larger working elements. The high speed cutting belts have an attachment point which allows the working element to be twisted on the top exterior surface of the belt. Obviously, such twisting reduces the conveying ability of the system.
For slow speed type belts, the working element is typically larger which, because of an increased moment arm, makes it easily deflectable. An example of an integrally molded working element in the form of a lug is shown in U.S. Pat. No. 2,637,436. Working elements in this type of belt are not replaceable. While the integrally molded system is perhaps good for some conveying systems it also has problems. The belt bends chordally around pulleys which highly stresses the working element and belt at the point of attachment. Cracks appear at the base of the working element which may cause the lug to be eventually pulled off. The lug is then irreplaceable. Such problems lead to the development of a new class of belts where the working element is attached by means of two longitudinally spaced fasteners.
In some of these belts, a solid molded working element is attached with longitudinally spaced fasteners. Others use metal or plastic straps bent to a V-shape with the apex of the V oriented away from the top of the belt and the two sides of the V bent to form a small tab that is attached to the belt with longitudinally spaced fasteners. The theory of the strap type element is that it will reduce chordal bending of the belt as it operates around sheaves by permitting portions of the V-shape strap to bend. While the effects of chordal bending may be reduced to such a device, a problem of flex fatigue of the strap material is introduced which leads to early failure of the working element.